This invention relates to a pivoting arrangement for connecting an actuator to the outboard drive portion of a marine propulsion unit and more particularly to an arrangement for strengthening the pivotal connection without significantly increasing its size and by simplifying its construction to reduce cost.
As is well known, many marine propulsion systems, particularly ones having larger displacements employ hydraulically operated trim and tilt controls. These systems generally permit trim adjustment when the watercraft is in motion and tilting up out of the water for trailering or service. In addition they generally incorporate a pop up damping arrangement that permits the propulsion unit to pop up when an underwater obstacle is encountered to prevent damage and return to the trim adjusted position when it is cleared.
One such arrangement is shown in Published Japanese Application, publication number Hei 07-69289, published Mar. 14, 1995. As shown in that publication, the tilt and trim arrangement comprises a clamp bracket fixed to the watercrafthull and on which a propulsion unit is pivotally supported for the trim and tilt operation. This is accomplished by a tilt cylinder mounted with its axis extending in a generally vertical direction and capable of expanding and retracting in the axial direction. The lower end of the cylinder is pivotally supported by the clamp bracket through a lower pivot and its upper end is pivotally connected to the propulsion unit through an upper pivot. A pressurized oil control system for controlling oil delivery to accomplish the desired motion.
As seen in that publication both the upper and lower pivotal connections require at least one pin receiving that receives a respective, separate pin that must be somehow connected to the propulsion unit and the clamping bracket that forms the attachment to the hull of the associated watercraft. This increases the number of parts and the assembly operation and obviously the cost. Also the use of separate pins can decrease or prevent the increase of the strength of the unit. Although strength can be increased by increasing the size, the construction does not offer excess space for such a resolution to the problem.
In addition and particularly with the upper connection to the propulsion unit, a boss part is secured to the extended end portion of the piston rod and is of a generally hollow cylindrical shape to receive a pivot pin. Although the strength could be improved by increasing the diameter, surplus space in the outboard motor is limited and it is not easy to increase enough the outside diameter dimension of the boss part. Also since the pivot is provided by a pin in addition to the boss in the upper pivot member, the number of parts is increased and its construction and assembly is complicated.
Therefore it is a principal object of the invention to provide a pivoting arrangement for connecting an actuator to the outboard drive portion of a marine propulsion unit and more particularly to an arrangement for strengthening the pivotal connection without significantly increasing its size and by simplifying its construction to reduce cost.